/*
 * Copyright 2021 by LunaSec (owned by Refinery Labs, Inc)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */
import { createPrivateKey, KeyObject } from 'crypto';

const __SIGNING_KEY__ = process.env.LUNASEC_SIGNING_KEY;

export function environmentSecretProvider() {
  if (__SIGNING_KEY__ === undefined) {
    throw new Error('Unable to read secret from environment variable: LUNASEC_SIGNING_KEY');
  }

  let secretKey: KeyObject;
  try {
    const signingKey = Buffer.from(__SIGNING_KEY__, 'base64');
    secretKey = createPrivateKey(signingKey);
  } catch (e) {
    console.error(e);
    throw new Error(
      `Error loading Session Signing Key from environment, check your environment variable LUNASEC_SIGNING_KEY is formatted correctly`
    );
  }

  return Promise.resolve(secretKey);
}
